1. Field of the Invention
The present invention relates to an improved structure for the compositely formed sound box and is designed to reduce the thickness of sound box's shell, intensify the hardness of shell, and upgrade the soundproof performance of the sound box at the same time.
2. Description of the Prior Art
Conventionally, the sound boxes were made of woods. The plastic-made sound boxes became popular only in recent years. FIG. 1 shows the one-pieced sound box, which is stuffed with plastic material and is manufactured by the revolving-formed method and, consequently, the sound box is nothing but a box without any holes to accommodate any components. The intensified ribs and the inlet component's opening cannot be manufactured when the sound box is formed. Therefore, the sound box needs to be processed again after it is manufactured and requires additional costs. Another disadvantage originates from the manufacturing process. The plastic material is poured into the boiling molds first. As soon as the plastic material cools down, the same grade of bubbled plastic material is poured into the mold and is revolved in order to create a bubbled soundproof layer. The process takes 40 minutes, which is excessively time-consuming. Therefore, the production is limited to a certain level.
FIG. 2 shows the new sound box, which is made by the injection method. This method allows higher production speed and requires fewer costs. The box accommodates the intensified ribs and inlet components, but the soundproof performance is inferior. Additionally, the box has to be thicker than 5 mm so as to eliminate the noise generated by the shell when the voice comes through the sound box.
In an effort to solve these problems, the inventor has studied the aforementioned problems thoroughly and conducted several experiments before he invented the present invention.